Great news for all the Topobase users and 3rd party developers. Autodesk just published the full Autodesk Topobase 2010 help on www.autodesk.com/topobase-help. It is now available online and accessible from everywhere you are.
Here you find the direct link to each of the user guides:
Administrator Guide - Describes administrator tasks such as designing forms, creating reports, establishing rules for job management, setting up users and groups, managing workspaces, documents, configuration settings and topologies, customizing workflows, and creating and editing the data model.
Feature Rules Reference - Provides a brief overview of the concept of feature rules and includes sections that describe the basic server-side and client-side rules, the rules that you can use with feature classes in the Coordinate Geometry (COGO), Template, and Plot extensions, and rules that you can associate with the specialized feature classes of the Topobase vertical application modules.
Client User Guide - Provides explanations and procedures for using Topobase Client to display, create, edit, and analyze geometry and attribute data.
Web User Guide - Provides concepts and procedures for using Topobase Web.
Electric User Guides - The North American and Central European Electric User Guides describe the data models and workflows specific to the electric industry in those regions.
Gas User Guide - The Gas User Guide describes the data models and workflows specific to the gas industry.
Land Management User Guide - The Land Management User Guide describes the data models and workflows specific to land management.
Survey User Guide - The Survey User Guide describes the data models and workflows specific to surveying.
Wastewater User Guide - The Wastewater User Guide describes the data models and workflows specific to the wastewater industry.
Water User Guide - The Water User Guide describes the data models and workflows specific to the water industry.
Developer’s Guide - Describes how to use the Topobase API and associated sample code.
Also AutoCAD Map3D and AutoCAD Civil3D have their documentation online.